Conservative shadow cabinet office minister Alex Burghart told Sky News that he questioned whether any other members of the WhatsApp group called out Gwynne’s remarks at the time.

“That was a big WhatsApp group with a lot of other Labour members – did any of them step in at the time? Did any of them call that out?” he said.

He said the message about the elderly constituent was “sort of quite a nasty attempt to do down an old person”.

And he said the message about someone’s name sounding “too Jewish” was “sinister”.

“And that really does suggest that just beneath the surface, between all the sort of the window dressing that Keir Starmer has done that with senior Labour politicians, there may still be a very serious problem with antisemitism, and I hope that the prime minister will get to grips with that immediately,” Burghart said.

Pennycook added: “An investigation is taking place, and any action that needs to follow from that investigation will be seen through.

“I don’t think anyone can be in any doubt about this prime minister or this government’s commitment to upholding the highest standards in public office and to rooting out antisemitism from the Labour Party, root and branch.”

One Labour MP from Gwynne’s constituency area told the BBC the comments were “extraordinary”.

He said: “I know Andrew quite well. I’m surprised he would say these things, that any Labour MP would say those things.”

Gwynne was first elected as a Labour MP in 2005, representing the Denton and Reddish constituency. He was elected as MP for Gorton and Denton last year following a constituency boundary change.

Health Secretary Wes Streeting appointed him to the junior ministerial role in the Department of Health and Social Care after Labour won government in July 2024.

He is the third MP to leave the government since last summer’s election, coming after the departures of Tulip Siddiq as Treasury minister in January and Louise Haigh as transport secretary last November.

Siddiq stepped down over allegations linked to her aunt’s political movement in Bangladesh, while Haigh resigned after it emerged that she had pleaded guilty to a criminal offence related to the reported theft of a work mobile phone.